Design, development and implementation of a biomechanical right-hand prosthesis: Second stage

This document presents the development of a right-hand biomechanical prosthesis. This artificial limb provides range of motion to a person whose hand has been amputated at the wrist level, allowing them to grab objects through a cylindrical grip, lateral grip, tip grip and twisting of the wrist, helping the patient to perform daily activities like drinking water, holding pens, typing, and holding flat and cylindrical objects. This research is carried out in two phases: during the first phase a prototype was developed that allows for movement of the fingers using a system of links that integrates a micro controller commanded through signals relayed from an optical sensor placed 10 mm from the stump of the patient; in the second phase a prototype that improves the anthropometry and aesthetics of the prosthesis by taking measurements and 3D scanning of a human hand is developed, it also integrates the rotating movement of the wrist using a broached axle and cube system that allows the prosthesis to rotate 360° on its own axis, the battery dimensions are also reduced and it is placed on the back of the prosthesis; to ensure that the forearm is fastened, a low-weight socket is developed to accommodate the rotating system. About 70% of the components are 3D-printed and the remaining 30% are obtained through conventional machining processes. The result is a prosthesis that allows up to 37 sequences, featuring a non-invasive, easy to manipulate control system and a cost of less than 3,000 dollars, lastly, implementation of the prosthesis is done on a right-hand amputee, who manages to control the prosthesis within three months of daily practice.